Relationship between volume and outcome for gastroschisis: a systematic review protocol

BACKGROUND: Gastroschisis is a congenital anomaly that needs surgical management for repositioning intestines into the abdominal cavity and for abdominal closure. Higher hospital or surgeon volume has previously been found to be associated with better clinical outcomes for different especially high-risk, low volume procedures. Therefore, we aim to examine the relationship between hospital or surgeon volume and outcomes for gastroschisis. METHODS: We will perform a systematic literature search from inception onwards in Medline, Embase, CENTRAL, CINAHL, and Biosis Previews without applying any limitations. In addition, we will search trial registries and relevant conference proceedings. We will include (cluster-) randomized controlled trials (RCTs) and prospective or retrospective cohort studies analyzing the relationship between hospital or surgeon volume and clinical outcomes. The primary outcomes will be survival and mortality. Secondary outcomes will be different measures of morbidity (e.g., severe gastrointestinal complications, gastrointestinal dysfunctions, and sepsis), quality of life, and length of stay. We will systematically assess risk of bias of included studies using RoB 2 for individually or cluster-randomized trials and ROBINS-I for cohort studies, and extract data on the study design, patient characteristics, case-mix adjustments, statistical methods, hospital and surgeon volume, and outcomes into standardized tables. Title and abstract screening, full text screening, critical appraisal, and data extraction of results will be conducted by two reviewers independently. Other data will be extracted by one reviewer and checked for accuracy by a second one. Any disagreements will be resolved by discussion. We will not pool results statistically as we expect included studies to be clinically and methodologically very diverse. We will conduct a systematic synthesis without meta-analysis and use GRADE for assessing the certainty of the evidence. DISCUSSION: Given the lack of a comprehensive summary of findings on the relationship between hospital or surgeon volume and outcomes for gastroschisis, this systematic review will put things right. Results can be used to inform decision makers or clinicians and to adapt medical care. SYSTEMATIC REVIEW REGISTRATION: Open Science Framework (DOI: 10.17605/OSF.IO/EX34M; 10.17605/OSF.IO/HGPZ2)